Abstract: In order to solve the load balancing problem of the low earth orbit (LEO) satellite network which has a dynamic topology, a routing algorithm based on left load rate is proposed first in this paper. Then this routing algorithm is used in the routing algorithm combining the genetic algorithm and ant colony algorithm. Genetic algorithm is used to generate the initial results and then they are transformed into the initial pheromones value of the ant colony algorithm. Lastly the ant colony algorithm is used to generate the best routing. Simulation results indicated that the routing algorithm proposed in this paper balanced the network traffic effectively, increased the network throughput, reduced the network delay and improved the performance of the satellite network.